I was in a game with other players, suddenly I was unable to move and and noone would reply, in short the game had dropped me and not told me.

So I go back into the game, after waiting a long time to get past the reply, I was reassigned my spot. Someone had left and I was assigned their spot, but I couldn't move the unit.

Shortly after this I got the following error which disconnected me again. (I think that is generally what happened, I haven't been able to connect to the forum either, and I am really tired and finding it hard to recall, but I wrote down the error exactly)

The bug I just experienced isn't a "missing child error" but it's related to it, and I don't want to open a new thread just for it.
So, err, I was playing some survival and one of my spearmen had 8/24XP. I decided to level it up so I managed to get it to kill a Troll Rocklobber, but right at the finish blow I got a missing child error which made me quit. When I came back, the host gave me my side back and that spearman had 24/24XP but whithout option to level him up.
I am reporting this bug (which I think is more of a glitch than a bug) because it angered me that a mage spawned right when I ended my turn and killed the spearman before my next turn.

Please fill an bug report at https://bugs.wesnoth.org and include a map which causes this issue.
And are you using 1.14.x or a version of the 1.13.x series — if so, please retry with 1.14.3, as such a bug has been fixed during 1.13.x.

In the future, please start a new thread instead of writing in an 8 years old one — people may have talked about a different bug in wesnoth 1.8.x.